There is currently known the technique regularly used for transpedicular vertebral attachment using a normal five centimeter long screw.
This technique suffers from drawbacks derived from the very dimension and constitution of the screw and of the anchorage site, which may cause rocking of the front end of the screw, proper to osteoporotic vertebrae, with the consequent loss of pull-out strength and with the serious risk of extending beyond the vertebra anterior cortical layer with the tip of the screw, possibly perforating viscera or blood vessels.